


Sin With a Grin

by Sparklefuzz94



Category: Supernatural
Genre: Castiel is a demon, Crowley is dead, Dean is Bad at Feelings, Fluff and Smut, Jealous Castiel, Knight of Hell Castiel (Supernatural), M/M, Mark of Cain, The Empty
Language: English
Status: In-Progress
Published: 2017-10-04
Updated: 2017-10-04
Packaged: 2019-01-08 23:00:24
Rating: Teen And Up Audiences
Warnings: Major Character Death
Chapters: 1
Words: 3,664
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12263844
Author URL: https://archiveofourown.org/users/Sparklefuzz94/pseuds/Sparklefuzz94
Summary: Crowley and Castiel both die and are sent to the Empty. Crowley wants revenge on his mother's death and Castiel wants to get back to Dean. Crowley and Castiel come up with a way to get one of them out of The Empty and back to the Winchesters, to save the world from Lucifer





	Sin With a Grin

Castiel made it back through to the other side of portal just as it began to close. He didn’t have time to see if his angel blade had killed Lucifer and he didn’t really care. All he could hear, ringing in his ears was Dean yelling to him. He needed to get back to him; needed to keep him safe, like he always did. But then something happened just seconds on the other side of the portal; back in their world.  
Castiel locked eyes with Dean; the two of them slowly smiling. He took one step towards the man he raised from Perdition; the man he would do anything for. And then he felt it. The piercing, white hot pain of an angel blade. It started at his wings, into his shoulder blade and out through the center of his chest. Before he had time to react, everything was gone.  
Several minutes passed and all he saw, felt and smelled was darkness. This was different than all the other times he, Castiel, had died. He would end up in Heaven, normally in his favorite field filled with wildflowers and buzzing bumble bees. This time, there was nothing. Was this The Empty that Billie had talked about?   
God had never briefed him on The Empty. It wasn’t a place angels could be sent, but neither was Purgatory and he somehow ended up there as well. Wherever he was, all of his nerves were on end. The only good thing was the pain from being stabbed was gone.   
He tried everything to get some light to appear; snapped his fingers, clapped his hands, called for light. Nothing worked. He could feel himself walking, but on what? When he leaned down to touch the ground, his hand kept going; unable to feel anything. He began to run his hands over his body, realizing it was odd that he even had hands or a body. Every other time he died, his essence and grace just sort of floated around, since he didn’t have a use for a vessel.   
He kept feeling himself over, feeling a tie, a suit jacket and his trench coat. This did nothing but add to his confusion. It also didn’t help that he was beginning to hear voices off in the distance. The tone of their voices suggested they were arguing. He wanted to hide behind something, but there was nothing. The voices kept getting closer. As they did, he recognized the voices as Billie and Crowley.   
“I don’t care if angels are or aren’t supposed to be here. I said the next time a Winchester died, they were coming here. Castiel has called himself a Winchester before, so I took him. An eye for an eye,” Billie’s smooth, cold voice was casually explaining.   
“Team Free Will is the only hope for getting Lucifer back in the bloody cage!” Crowley yelled. “I did my part. I trapped him in the alternate universe. We both know Squirrel and Moose can’t bloody well do this alone; they need their pet angel!”   
The voices were right in front of him, yet Castiel couldn’t see them. Their voices sounded muffled.  
“Does it look like I care?” Billie asked. “When I get stabbed to death, I tend to not want to do anything to help my assailant.”   
“My time on Earth is done. I’m perfectly content to stay here for eternity. I’ll do everything in my bloody power to get that feathered arse back to the Winchesters,” Crowley’s thick accent drawled out, making Castiel tilt his head to the side.  
“Why do you care so much?” Castiel asked, his voice sounding exactly like his vessel’s.   
“Ah, Feathers, I see you’ve made it to the party,” Crowley said with a clap of his hands.  
Castiel looked around, expecting to see balloons and streamers. He still saw nothing but darkness. “I don’t see a party,” Castiel deadpanned.   
Crowley scoffed, “Always so literal.” He paused, making Castiel uncomfortable. “I care because Lucifer killed my mother. I’m the only one allowed to kill that naggin’ bitch.”  
“So, you want revenge?” Castiel tilted his head again. “Yet you don’t want to leave here?”  
“And that’s why your feathery arse is gonna go back down to your boyfriend and Moose. I have little faith in our boys getting’ the job done-correctly. Especially now that Mother’s gone.” He paused. Castiel crossed his arms, waiting for the “but.” There was always a “but” with Crowley. “You ain’t gonna like how I’m sending you back down, though.”  
Castiel’s skin crawled with those words. “Whatever you’re going to do, will there be a cure for it?”  
“Yeah, if yaw anna end up back here. Castiel, Lucifer stabbed your vessel in the heart. If you eject or reject my little fix, you’ll die and end up back here with me for all of bloody eternity. Your boyfriend will accept you, don’t worry.”  
“I wish you wouldn’t call Dean that,” Castiel mumbled, feeling himself growing more concerned.  
Crowley ignored him and continued, “We need to gather as many souls as we can. I’m pretty weak right now and to send you back as a Knight of Hell, at the bloody least, is going to take time.”  
“A Knight of Hell?” Castiel choked out.  
“Did I friggen’ stutter?” Crowley squeaked. “Yes, a Knight of Hell. It’s gonna take at least that much power for ya to send Lucifer back to the cage. Once ya get back down there, you’re gonna need more souls. You’re quite proficient at collecting souls, so no need to worry there.”  
“I try not to remember, nor relive my past,” Castiel replied.  
“Oh, Cassie, you’re gonna be doin’ a lot more than relivin’ your past as a Knight of Hell,” Crowley said with a chuckle.  
“I let Lucifer in. He was selfish, undisciplined and reckless- “  
“What makes you think a Knight of Hell is any different?”  
Castiel didn’t have an answer. He had heard all about Dean’s time as a Knight of Hell. He drank what and when he wanted. He slept when he wanted, or not at all. Castiel heard in excruciating detail about his time with the male twins, along with many other females. That was what hurt the most and he could never tell Dean.  
“I sense you’re thinking about what this will do to your boyfr-uh Dean. Remember Feathers, he was a Knight of Hell- “  
“Yes, for six whole months. I heard every detail from you while we were working together. Did you really have to explain your orgy in great detail?” Castiel pinched the bridge of his nose.  
“Anything to get a rise outta ya.” He paused again. “Being the Knight of Hell will finally grow ya a pair. Maybe then you’ll do somethin’ about your disgustin’ pining over Squirrel,” Crowley replied, sounding a little bitter. Castiel picked up on this and his stomach churned with jealousy. Crowley tasted the jealousy in the air and continued with a smile, “If he let the King of Hell touch him, what’s to say he won’t lower his standards to a Knight of Hell.”  
Castiel swung his fist out, connecting with something. He heard Crowley swear, along with bone crunching. He felt his knuckles to see if they were bleeding. Nothing was there. “Leave Dean out of this,” Castiel spat, his voice dark.  
“Hey! He asked for it,” Crowley said, trying to justify his actions.  
Castiel let his arm drop, along with his heart.   
“But it wasn’t me he wanted in his bed,” Crowley added and then cleared his throat. “Ok, now that we’ve shared that touching moment…”  
“How do I know when I’ve found another soul in here?” Castiel asked, changing the subject, trying not to think about how Dean had at least lusted over him.  
“What do you mean? There’s at least twenty souls starin’ at us this whole bloody time. Are ya blind?” Crowley asked.  
Castiel shuddered involuntarily, “I see and feel nothing, Crowley. Angels were not meant for the Empty.”  
“That would explain that sissy swing to my ribs,” Crowley mumbled. “This’ll take more power outta me, and require more souls,” he said as he snapped.  
Suddenly Castiel could see. Crowley was standing to the left of him, giving him a clear shot of all the other lost souls. Each were looking down at the grey carpet they all stood on. Castiel continued to look around, seeing he was in what looked like an office building, only there was no furniture, nothing but blank beige walls, a generic wooden door and grey carpet. He noticed that no one was moving. Then he noticed just how tired he suddenly felt.  
“Why are they all so still?” Castiel asked aloud.  
“Billie put you in the oldest Part of the Empty, thus, they are ancient. Some of them have been around since the mastodons,” Crowley explained as Castiel looked around again.  
They were dressed in heavy animal skins that had turned grey or lost all of their fur from over the centuries. He shuddered and looked back at Crowley as he snapped. Each soul slowly moved towards Crowley, glowing faintly. Castiel took a step back, watching as the souls sluggishly made their way to Crowley. After what seemed like forever, the room was finally empty. Castiel looked back at Crowley, “Now what?”  
“We move onto the next room,” Crowley said as he began walking, Castiel slowly moving behind him.

This continued for many days, or what Castiel thought was day. He quickly lost track. Did time pass the same as it did in on Earth?   
The two were careful to dodge Billie. When they finished one room, Crowley would turn half of what they reaped into demons and pushed them into Castiel. The first time this happened, Castiel’s grace fought it; smiting many of the demons. This frustrated both of them, but they prevailed. Each time that Crowley shoved more demons in, Castiel could feel his grace weakening and being replaced by the powers of the demons. Crowley could tell too, as Castiel’s natural glow about him was growing dim with each treatment.   
More time passed. The two talked as little as possible, as Castiel didn’t want to share his feelings. With each treatment, he could feel his humanity slipping away, being replaced by dark thoughts of murder, revenge and taking what he thought he deserved. He didn’t really need Crowley anymore, but holding onto him was his only ticket back to Dean.  
Dean was a whole other can of worms he wasn’t ready to open yet. He let a few thoughts slip through. All of them ended in sexual fantasies of what he wanted to do to Dean the first time he was alone. It confused him how he gained the knowledge for so many sex positions with only sleeping with one person. He wasn’t worried about the strength it would require for some of those positions, as he felt himself growing stronger with each round Crowley fed him.

Several more rounds went in silence. Castiel was the first to break the silence with the statement, “The mark of Cain.”  
Crowley stopped his walk out of another barren room and looked back at the mostly demon Castiel. He could tell the angel part was still fighting the demons inside, but wasn’t winning. “What?” he asked, wiping his hands on his kerchief.  
“That would kill Lucifer, no?” Castiel asked, tilting his head to the side.  
Crowley shrugged, dapping the dark paisley kerchief at the corners of his mouth, “I suppose so.”  
“Then I need it. Why trap my brother when I can kill him? End this damn war, once and for all?” Castiel asked, the tiny sliver of angel protesting at killing one of his brothers. The demons were quickly able to bury it.  
Crowley clicked his tongue a few times, “My, my, my, I think our fine feathered friend has left the building…” He looked away, staring at the blank wall. Then he looked back at Castiel, “Well, ya already know where the first blade is… Why not add the mark to the mix?” He paused and really looked at Castiel. “We need to get the rest of angel out of you, in order for the mark to take hold fully.”  
Ten sessions later and the angel was finally gone. It sent Castiel to his knees, his eyes squeezed tight, as the tiny morsel of grace fought the demons as much as it could. Castiel could feel himself being smited from the inside out. He could feel a few demons being burnt off, which quickly angered them. A battle broke out inside of this, literally tearing up his insides. As this was happening, he could feel his wings being broken and burned. All of this was too much and he passed out.  
Crowley ushered the two of them into an empty room, but they didn’t go unnoticed. They had moved up to the late 1600s, so the souls weren’t as slow to move. Some of them fought back when Crowley and Castiel were reaping them.   
Crowley quickly closed the door behind them as Castiel fell to the floor like a sack of potatoes. “Oh, bloody hell,” he cursed under his breath. As he did so, the outline of Castiel’s wings appeared and the faint light of his grace appeared to burn out. A few minutes later, the carpet around him began to smolder and Castiel slowly sat up, his eyes still closed. He turned his head to look at Crowley and his eyes suddenly blinked opened. The crystal blue eyes were gone and replaced by the customary dark eyes of a demon. Crowley smiled, “It’s time for Amara.”  
Castiel slowly stood up, stretching along the way. He rolled his neck and shoulders once he was standing and then looked at Crowley with a dark smile, “Cassie’s home.” He walked over to the door that was being banged upon and yanked it open. Snapping, all of the souls were being drawn into him. He looked back at Crowley, stalking over to him. “I’m glad you’re annoying ass in stuck here. If I had to hear one more story about how you fucked Dean senseless, I was gonna kill ya again.” He got into Crowley’s face and growled low, “Dean is mine and will always be mine.”  
Crowley took a step back, shoving Castiel’s pointing finger away, “I see we aren’t afraid to speak our mind now.”  
“If you boys are done having a pissing contest,” Amara’s sultry, confused voice said from beside him. “Why did you call me here, Uncle Crowely?” She looked Castiel over and frowned, “Why is he a demon? What’s going on?”  
“Ah yes, my pet. If you would let me explain,” Crowley said, walking towards her slowly. “We need the mark.”  
She frowned again, looking between the two men, “Why?”  
“So I can kill Lucifer,” Castiel said, sounding bored.  
She folded her arms across her chest, “What’s not to say the first thing you do is kill me?”  
“Dean had the chance and didn’t kill you. I trust Dean,” Castiel said, growing impatient.  
She looked between the two of them. After a few seconds she shrugged her shoulders and walked over to Castiel. She looked into his eyes that had returned to their brilliant blue and sternly said, “I will not be held responsible for what you do with the mark.” Castiel nodded and she gripped his forearm. The skin instantly began sizzling, but Castiel welcomed the pain. The pain actually excited something inside of him.  
All too soon the mark was burned into his skin and her hand was removed. He looked back at Amara and growled, “Dean is mine. Don’t ever kiss him again.”  
Amara looked confused and took a step back. She shook her head and then disappeared into a cloud of wispy black smoke. Castiel looked down at his forearm, the mark glowing a faint red as he honed into the location of the blade; in a colony of bees in South Carolina. He was sure the bees had begun to build a hive around the blade. A small part of his was sad to know he would be destroying part of their home, but the bigger part craved to touch the blade; to feel the power of the blade.   
“Castiel,” Crowley said, his head snapping to attention. “I need some more souls. At least another century or two, before I can send you back.”  
“Make it quick. It has been too long without Dean,” Castiel said, looking down at his arm again. His hand was shaking slightly. He made a fist and it stopped. He slowly rolled down the three levels of shirts he had on.

The next three days, or what Castiel thought were three days, passed. He spent most of his time thinking about Dean and all of the times he was close to acting upon his actions. He knew when he came back, despite how much he just wanted to shove Dean up against a wall and make out with him, he would have to act as though he was still an angel. It shouldn’t be too hard, though Sam might catch on. It would be hard not to just come out and tell Dean what was going on.   
As for the plan of killing Lucifer, he was sure Sam and Dean would be on board with this. They wouldn’t be too happy with him being a Knight of Hell. Dean would probably try and cure him, which will make Castiel insist on keeping him alive. He would give the mark back to Amara once the job was done, maybe slowly let some of the demons go. Did he really need to be a Knight of Hell to live happily ever after with Dean?  
It was during one of these lost in thoughts moments that he sensed Crowley coming for him. The thought of seeing Dean again made him absolutely giddy. Getting one of those tight embraces that always lingered for a few too many moments was going to be the highlight of his day. He stood up from sitting with his legs crossed on the floor just as the door opened.   
“I called in a favor. Your body has been laying in the basement of the bunker, back where I was kept,” Crowley explained, waiting for Castiel to catch on. Several seconds ticked by and Crowley sighed. “Your body is laying on the table in the center of the devil’s trap. You’re going to be trapped.”  
“Fuck,” Castiel swore and began to pace. “I didn’t want them to know about this.” He blinked, his demon eyes showing for a second and then went back to their normal blue. “Right away.”  
“Life ain’t always easy, princess. Would ya rather be trapped here, without your precious Deano?” Crowley sneered. “I don’t wanna spend another minute longer with your moping arse.” He raised his hand, power crackling as he did so. “So, it’s no longer my problem, Feathers.” He snapped, the sound echoing.  
Castiel blinked once and gasped. He slowly sat up, every bone in his vessel’s body protesting. He coughed a few times and looked around as he did. Crowley was right; he was sitting on a table, a white sheet draped over him. Below him was a devil’s trap. Jumping up from the table, the sound of his dress shoes clicking on the concrete floor startling him after so long of silent movements, he looked down at the trap. He could sit here and pretend like everything fine, hoping one of them would come down eventually. Or, he could use the table leg to scrape away some paint and walk free. He opted to go with the second option but quickly found out it wasn’t paint but a dyed part of the cement. He walked over to the chair, sighing as he did, preparing to sit and wait for quite some time. As he did so, he carefully rolled the layers up on his right arm until he could see the very bottom of the mark. Smiling, he rolled them back down and patted his pockets, finding he had a cellphone there. He pulled it out and saw the date was ten months later. The phone was at one percent and then shut off before he could do anything else with him. Time definitely did not pass the same way in The Empty.  
He sat down in the chair, frowning. Was Dean really that hung up on him that he wouldn’t let Sam give him a hunter’s funeral? Was the sheet really necessary? So many questions swirled through his mind; the biggest two being about Dean and Jack. He could sense Jack was in the Bunker. He was much older than a baby and didn’t seem as evil as everyone was saying he was going to be. Castiel smiled, knowing he was right. 

Being able to count the hours the right way, Castiel realized he had been sitting in the same spot for three days, ten hours and twenty-three minutes before the door opened. He smiled as he felt Dean’s soul approaching.   
“Dean, it’s been ten months exactly,” Sam’s voice softly said as the outer door opened. Castiel could feel sympathy radiating off the younger Winchester, but he didn’t care. He wanted, needed to see Dean.  
“I don’t give a fuck, Sam. Yeah, it’s been ten months, but not one thing on him has started to decompose. There wasn’t any damn blood the next mornin’, man,” Dean said, his voice sounding slurred.  
Castiel’s smile faded. Dean was still mourning his death, and in his normal way. The jealous side of his wondered how many bitches he was going to have to kill before the night was over.  
The hidden shelves door opened. Sam’s figured appeared first as he was looking back at Dean. Dean was holding a beer bottle that quickly slipped from his hand, the glass shattering. “Sonofabitch,” he whispered.  
“Hello Dean.”


End file.
